Category: prosthodontics

Implant abutment screw retrieval -What every Dentist should know

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~Precision in action: Retrieving a fractured implant abutment screw to restore implant function and stability

Dental implants have revolutionized the way we replace missing teeth. With proper planning and execution, they offer excellent long-term success. However, like any mechanical system, implants can occasionally face complications. One situation clinicians may encounter is- loosening or fracture of an implant abutment screw.
Although it may initially seem alarming, a fractured abutment screw does not necessarily mean the implant has failed. In many cases, the screw fragment can be retrieved safely with the right technique and instruments.


Why Do Abutment Screws Loosen or Fracture?


Implant abutment screws are designed to withstand significant functional forces.  Factors which  may lead to loosening or eventual fracture:

1)Inadequate torque during placement
2)Occlusal overload
3)Poor implant–abutment fit
4)Parafunctional habits such as bruxism
5)Repeated screw loosening causing metal fatigue


Over time, these factors can weaken the screw and lead to fracture within the implant.


How Do You Recognize the Problem?


Patients may report that their implant crown feels loose or unstable while chewing. Sometimes they may simply notice a slight movement in the prosthesis.
Clinically, you might observe:


1)Mobility of the implant crown
2)Difficulty tightening the prosthesis
3)Occlusal discomfort
4)Radiographic evidence of a separated screw fragment


Once confirmed, the next step is careful retrieval of the remaining screw fragment.


Armamentarium Needed:


Having the right instruments makes the procedure much easier. Commonly used tools include:
1)Implant screw retrieval kit
2)Ultrasonic scaler with fine tips
3)Dental explorer or probe
4)Round or carbide bur
5)High-speed handpiece
6)Magnification (loupes or microscope)
7)Micro forceps or endodontic files


Step-by-Step Method for Screw Retrieval:


1. Careful Assessment
Begin with a thorough clinical and radiographic evaluation to determine the position of the fractured screw fragment.
2. Remove the Prosthesis
The crown or prosthetic component should be removed to allow clear access to the implant platform.
3. Visualize the Screw Fragment
Good lighting and magnification are extremely helpful at this stage. Clear visualization helps prevent damage to the implant threads.
4. Attempt Gentle Counter-Clockwise Rotation
Often, fractured screws lose their preload and are not tightly engaged. Using a sharp explorer, ultrasonic tip, or a fine endodontic file, gently attempt to rotate the fragment in a counter-clockwise direction.
5. Use a Retrieval Kit
If the fragment does not move easily, a manufacturer-specific screw retrieval kit can be used. These kits contain specially designed instruments that engage the broken screw and help remove it safely.
6. Create a Small Slot (If Necessary)
In some cases, a tiny slot can be prepared on the surface of the screw using a small bur. This allows a flat driver to engage the fragment and unscrew it.
7. Ultrasonic Assistance
Ultrasonic vibration may help loosen the fragment by disrupting the mechanical binding between the screw and implant.
8. Inspect the Implant
Once the screw fragment is removed, the internal implant threads should be carefully examined and cleaned to ensure there is no debris or damage.
9. Place a New Screw
A new abutment screw should be inserted and tightened according to the manufacturer’s recommended torque value.
10. Reinstall the Prosthesis
Finally, the prosthesis can be repositioned and secured after confirming the stability of the new screw.

The clinical case which is illustrated in this blog post ,the abutment screw fracture happened inrt 46.Implant placement was done  inrt 46 47 around 3 years ago and individual implant crowns (FP1) were placed .The patient reported with Dislodged implant crown inrt 46 .Radigraphic examination shows abutment screw fractured and lodged within the implant fixture.


Treatment planning included careful retrieval of abutment screw after mid crestal incision and flap elevation followed by retrieval using engaging the visible screw  tip with artery forcep with firm press and anticlockwise rotation to disengage the screw from the fixture.This was followed by placing of healing abutment inrt 46 and suturing and follow up after 1 week for suture removal.

Practical Tips for Clinicians:


-Always work under magnification and proper illumination
-Apply minimal force to protect the implant threads
-Use manufacturer-specific retrieval kits when available
-Take your time—patience often makes the difference


Preventing Future Screw Complications:


Prevention is always better than repair. The following steps can help reduce the risk of screw loosening or fracture:
1)Following correct torque protocols
2)Designing proper occlusion
3)Applying principles of implant-protected occlusion
4)Scheduling regular follow-ups for maintenance


Final Thoughts~


A fractured implant abutment screw can feel like a frustrating complication, but in most cases it is manageable with careful technique and the right instruments. With proper diagnosis and a systematic retrieval approach, the implant itself can often be preserved, allowing the prosthesis to continue functioning successfully for years.

#abutmentscrew #dentalimplants #implantology #prosthodontics #prosthodontist #screwretrieval #techniques #principles #implantfailure #handytips

Cantilever abutments (2m)

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  1. A cantilever abutment is a type of dental prosthesis where an artificial tooth is supported by only one natural tooth
  2. The forces applied such as vertical, torsional, and bending forces to the prosthesis can cause the screw holding it in place to become loose or break, and the abutment tooth may also fracture
  3. Using a cantilever bridge with a resin coating has been found to be a reliable way to replace missing teeth in the lower jaw.
  4. The use of a support system with a short implant and ball-type abutment can reduce stress distribution and displacement in the cantilever extension of dental prostheses.

Prosthodontic Strategies for Bruxism Management and Dental Protection

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Bruxism, which is characterized by the repetitive clenching or grinding of teeth, is a common phenomenon that can have negative consequences on oral health and overall well-being (Yap & Chua, 2016). It is important to manage bruxism to prevent dental problems such as tooth wear, fractures of dental restorations, and pain in the oro-facial region (Koyano et al., 2008). The management strategies for bruxism mainly focus on reducing the potential negative consequences and controlling the symptoms associated with bruxism (Gouw et al., 2018).

One approach to managing bruxism is through the use of occlusal splints or oral appliances. Occlusal splints are commonly used for the diagnosis and treatment of bruxism, and they work by providing a protective barrier between the upper and lower teeth, reducing the impact of grinding and clenching (Ali et al., 2023). These splints can be effective in preventing tooth wear and reducing muscle pain and headaches associated with bruxism (Raby et al., 2018). However, it is important to note that occlusal splints do not eliminate bruxism, but rather serve as a means of managing its consequences (Raby et al., 2018).

Another management strategy for bruxism is the use of botulinum toxin injections into the masseter muscles. This treatment temporarily reduces the frequency of bruxism events and can provide relief from symptoms such as muscle pain and headaches (Serrera-Figallo et al., 2020). However, it is important to note that the current treatment modalities for bruxism are not effective and feasible for most patients with sleep bruxism (Gouw et al., 2018). Therefore, a multimodal approach that combines different treatment modalities may be recommended for managing bruxism (Gouw et al., 2018).

In addition to these treatment modalities, it is important to consider the underlying causes and contributing factors of bruxism. Bruxism is believed to be regulated centrally, with pathophysiological and psychosocial factors playing a role in its development (Yap & Chua, 2016). Stress sensitivity and anxious personality traits have been identified as potential factors that may contribute to bruxism activities and temporomandibular pain (Manfredini et al., 2017). Therefore, addressing these factors through stress management techniques, relaxation training, and behavioral therapy may be beneficial in managing bruxism (Kumar et al., 2022).

Furthermore, the management of bruxism should also take into consideration the potential impact on dental restorations and implants. Bruxism is considered a contraindication for dental implants, as it may cause overload and failure of the implants (Lobbezoo et al., 2006). Therefore, careful consideration should be given to the use of dental implants in patients with bruxism, and protective measures such as occlusal guards may be recommended to minimize the risk of implant failure (Yang et al., 2022).

It is worth noting that the management of bruxism should be tailored to the individual patient, taking into account their specific needs and circumstances. The use of observational and non-interventional management strategies may be appropriate for younger children, as the majority of bruxist children do not continue to brux during adolescence and adulthood (Manfredini et al., 2013). On the other hand, adults with bruxism may require more comprehensive management strategies to address the consequences of bruxism and alleviate symptoms (Manfredini et al., 2019).

In conclusion, the management of bruxism involves a combination of strategies aimed at reducing the negative consequences of bruxism and controlling its symptoms. These strategies may include the use of occlusal splints, botulinum toxin injections, stress management techniques, and behavioral therapy. It is important to tailor the management approach to the individual patient and consider the potential impact on dental restorations and implants. Further research is needed to better understand the underlying causes of bruxism and develop more effective treatment modalities.

References:

Ali, F., Alsheri, M., Shami, S., Mohana, A., Abujamilah, E., Alshehri, F. (2023). A Case Report Of Bruxism and Its Management With The Help Of Occlusal Splints.. Int J Life Sci Pharm Res. https://doi.org/10.22376/ijlpr.2023.13.2.l27-l30 Ali, S., Alqutaibi, A., Aboalrejal, A., Elawady, D. (2021). Botulinum Toxin and Occlusal Splints For The Management Of Sleep Bruxism In Individuals With Implant Overdentures: A Randomized Controlled Trial. The Saudi Dental Journal, 8(33), 1004-1011. https://doi.org/10.1016/j.sdentj.2021.07.001 Gouw, S., Wijer, A., Kalaykova, S., Creugers, N. (2018). Masticatory Muscle Stretching For the Management Of Sleep Bruxism: A Randomised Controlled Trial. J Oral Rehabil, 10(45), 770-776. https://doi.org/10.1111/joor.12694 Koyano, K., Tsukiyama, Y., Ichiki, R., T, K. (2008). Assessment Of Bruxism In the Clinic. J Oral Rehabil, 7(35), 495-508. https://doi.org/10.1111/j.1365-2842.2008.01880.x Kumar, A., Nair, A., Faizal, F., S, S., Prasad, M. (2022). Diagnosis and Management Of Sleep Bruxism. JPID. https://doi.org/10.55231/jpid.2022.v05.i02.04 Lobbezoo, F., Brouwers, J., Cune, M., Naeije, M. (2006). Dental Implants In Patients With Bruxing Habits. J Oral Rehabil, 2(33), 152-159. https://doi.org/10.1111/j.1365-2842.2006.01542.x Manfredini, D., Ahlberg, J., Winocur, E., Lobbezoo, F. (2015). Management Of Sleep Bruxism In Adults: a Qualitative Systematic Literature Review. J Oral Rehabil, 11(42), 862-874. https://doi.org/10.1111/joor.12322 Manfredini, D., Colonna, A., Bracci, A., Lobbezoo, F. (2019). Bruxism: a Summary Of Current Knowledge On Aetiology, Assessment And Management. Oral Surg, 4(13), 358-370. https://doi.org/10.1111/ors.12454 Manfredini, D., Restrepo, C., Díaz-Serrano, K., Winocur, E., Lobbezoo, F. (2013). Prevalence Of Sleep Bruxism In Children: a Systematic Review Of The Literature. J Oral Rehabil, 8(40), 631-642. https://doi.org/10.1111/joor.12069 Manfredini, D., Serra-Negra, J., Carboncini, F., Lobbezoo, F. (2017). Current Concepts Of Bruxism. Int J Prosthodont, 5(30), 437-438. https://doi.org/10.11607/ijp.5210 Minervini, G., Fiorillo, L., Russo, D., Lanza, A., D’Amico, C., Cervino, G., … & Francesco, F. (2022). Prosthodontic Treatment In Patients With Temporomandibular Disorders and Orofacial Pain And/or Bruxism: A Review Of The Literature. Prosthesis, 2(4), 253-262. https://doi.org/10.3390/prosthesis4020025 Raby, I., Quiroz, D., Galleguillos, P. (2018). Freely Available or Over-the-counter Occlusal Splints Obtainable In Commercial Outlets: A Reality Dentists Should Know. J Oral Res, 7(7), 219-226. https://doi.org/10.17126/joralres.2018.063 Serrera-Figallo, M., Ruiz-de-León-Hernández, G., Torres-Lagares, D., Castro-Araya, A., Torres-Ferrerosa, O., Hernández-Pacheco, E., … & Gutiérrez-Pérez, J. (2020). Use Of Botulinum Toxin In Orofacial Clinical Practice. Toxins, 2(12), 112. https://doi.org/10.3390/toxins12020112 Sriharsha, P., Gujjari, A., Dhakshaini, M., Prashant, A. (2018). Comparative Evaluation Of Salivary Cortisol Levels In Bruxism Patients Before and After Using Soft Occlusal Splint: An In Vivo Study. Contemp Clin Dent, 2(9), 182. https://doi.org/10.4103/ccd.ccd_756_17 Yang, J., Siow, L., Zhang, X., Wang, Y., Wang, H., Wang, B. (2022). Dental Reimplantation Treatment and Clinical Care For Patients With Previous Implant Failure—a Retrospective Study. IJERPH, 23(19), 15939. https://doi.org/10.3390/ijerph192315939 Yap, A., Chua, A. (2016). Sleep Bruxism: Current Knowledge and Contemporary Management. J Conserv Dent, 5(19), 383. https://doi.org/10.4103/0972-0707.190007

TYPES bar-retained overdentures 2M*

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  1. One of the methods of retention of overdenture is bar attachment.
  2. The typical bar attachment consists of a bar connecting two or more abutments. Joining the two abutments enables splinting
  3. There are two types of bar attachments. 
    1. Bar joints permit rotational movement. 
      1. They are used as a splint connecting the abutments together
    2. Bar units (rigid fixation) permit no movement. 
  4. They are placed as a single unit on the abutment teeth like a stud attachment

REVERSIBLE HYDROCOLLOID = AGAR 2M*

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  1. reversible ( gel can change to paste by heating, then can change back to gel by cooling)
  2. a major component is seaweed – comes as collapsible tubes
  3. you boil it at 100° C for 10 mins then store at 65°C for 10 mins then temper at 43-46° C 5-10 mins before you take the impression
  4. agar can be stored at 65°C for 5 days before it has to be reboiled again 

ENAMELOPLASTY 2M**

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  1. Simple enameloplasty to reduce the severe curve of spee and adjust supra erupted teeth 
  2. Enameloplasty is defined as a procedure of recontouring a portion of the enamel to obtain the desired morphology
  3. A tapered diamond cylinder stone in a high-speed handpiece with air-water spray is used for the procedure.
  4. After the procedure, fluoride application is done by using plastic mouth guards.

Stress breaker 4m** 2m**

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  1. It is defined as a device, which relieves the abutment tooth of all or part of the occlusal forces (GPT) 
  2. In order to minimize the stress in the case of distal extension partial denture, devices like stress breakers are used.
  3. Type I = In this type, a movable joint is placed between the direct retainer and denture base.
  4. Type II  = This type consists of a flexible connection between the direct retainer and the denture base. 
  5. Advantages 
    1. Preservation of the alveolar support of abutment
      tooth due to the reduction of stress on it.
    2. Balanced stress on residual alveolar ridge and
      abutment.
    3. Weak abutment teeth are well splinted even when
      the denture base is moved.
    4. Even if relining is not done properly, abutment
      teeth are not damaged.
    5. Direct retention is less required.
    6. A massaging effect is produced on the soft tissues during the movement of the denture base.
    7. This lessens the need for frequent relining and rebasing.
  6. Disadvantages 
  • Complicated design and expensive.
  • Weak assembly and fractures easily.
  • It distorts due to rough handling.
  • It is difficult to repair.
  • It can counter only the vertical forces on the
    denture.
  • Reduced stability against horizontal forces.
  • Inappropriate relining leads to excessive ridge resorption.
  • Reduced indirect retention.
  • The split major connector tends to collect food
    debris at the area of split.

Soldering 2m**

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  1. is defined as joining two components of metal with an intermediate metal whose melting temperature is lower than the parent metal. 
  2. Types of soldering for metal-ceramic restoration 
    • Oven soldering
    • Torch soldering
    • Infrared soldering
    • Laser welding

Tripoding the cast 2m**

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  • Tripoding is a procedure where three different widely spaced out points of a single plane are marked on the cast.
  • To allow you to reposition the cast according to the selected path of insertion 
  • These tripod points are used as a reference point and they should not be altered until the treatment is completed.